Grey whale spotted in San Francisco Bay

A grey whale was spotted swimming off Marina Green at around 12:30 p.m. Experts say the whale appears to be a full-grown gray.

Those who happened to be walking along the waterfront told ABC7 they were taken by surprise. "I have never seen one in the bay before," said Juliana Beach. "I've seen them off Ocean Beach, but I've never seen them in the bay."

The sighting is not that unusual. About 30 whales a year find their way into the bay, almost all of them in the spring as they head back to their arctic feeding grounds.